How to start a program with bash -c, redirect / disable GUI of that app

Question

Currently I'm starting a java application with

bash -c java -jar app.jar -config config.json

The app opens a window, displaying some output and closes. The output is also available on stdout, so I don't need (want) the GUI to display.

How can I prevent bash to forward the X output?

Follow up:

I'm running this in a go application, so based on el.pescado's answer, I have implemented this as:

func runcmd(cmd string, workdir string) ([]byte, error) {
  ex := exec.Command("bash", "-c", cmd)
  ex.Env = []string{"DISPLAY= "}
  ex.Dir = workdir
  return ex.Output()
}

score 2 · Accepted Answer · answered Nov 21 '18 at 10:07

You have several options:

First, you should check if that application can run without GUI (often called "headless" mode)
You can unset DISPLAY variable, so that your app won't find your X11 server - but keep in mind that application might not work without X server

eg.

DISPLAY= bash -c java -jar app.jar -config config.json # note space after '='
# or
env -u DISPLAY bash -c java -jar app.jar -config config.json

You could use in-memory virtual X server such as xfvb and point your application to display its windows there.

eg.

Xvfb :1 -screen 0 1600x1200x32
DISPLAY=:1 bash -c java -jar app.jar -config config.json

@mgagnon #2 `DISPLAY= bash -c java -jar app.jar -config config.json` — G-M, Nov 21 '18 at 12:42

How to start a program with bash -c, redirect / disable GUI of that app

1 Answers1